While I think statements such as "work with what you have" and "buy the proper tool for the job" are valid to a certain extent, in this industry there really is a little bit more to it.Let me try and explain my general feeling here on why certain equipment is chosen over another. (I'm not sure how well this will actually translate into words, but here goes my best shot.)
I am going to make this completely non-vendor specific so no one thinks I am pointing the blame finger at them. Let's pretend that there is a company that makes a full line of cinema equipment called "Cinemaco". Let's also pretend that they make an outstanding projector, a pretty reliable lamphouse and a decent automation, but for the sake of this argument (since this thread is on platters) let's say 99% of people who have used their platter experience at least one print dump a week or scratching. Cinemaco's platter is worse than the Eprad spoken above. (Is that even possible?) For the sake of this example, we will ignore other things such as screens, sound equipment, etc.
Enter Bob at Movie Theater Chain of America, who is going to open up a new theater and is in the position of deciding what kind of equipment to install. The way I see it there are 3 ways to come to that conclusion.
#1 Put the BEST in. Buy the best tool for each job. This of course means that in all probability between the projector, lamphouse, platter and automation that at least 2 manufacturers will be involved to obtain this, but possibly 3 or 4. (Let's be serious here, there is no manufacturer that makes the best this and the best that. There is ALWAYS one something-or-other in their equipment line that is less than ideal for the job.) This option requires a lot of money and a lot of effort, but in the end provides the best presentation (from an equipment standpoint) and the best reliability. The techs who have to service this theater now will have to spend very little time there and the projectionists will hardly ever have to deal with equipment breakdowns, damaged prints or even less-than-ideal equipment designs. For the rest of that theater's life, everyone is in heaven and this theater will be very inexpensive to keep running.
#2 Bob knows he does not have an unlimited budget, so he has his list of "top 3" choices for each item he needs to purchase. He decides what is most important and gets the best of that, then perhaps also gets his first choice on the second item, but on the third and fourth item he has to take his second, or even third choice. What Bob has done here is assemble a system between different manufacturers that is cost-effective, but smart. Lots of intelligence and thought has gone into this booth. The tech's job isn't too hard, for the equipment chosen is pretty darned reliable, although this or that could've been better for one reason or another. While this is not the ideal situation, it is a good and fair one that shouldn't be frowned upon.
#3 Bob calls up a couple of dealers and says "I need booth equipment for my new awesome state-of-the-art theater. Quote me some packages!" The dealers all then return their bids, perhaps each dealer provides 2 or 3 different priced packages. Bob then takes a long hard look at each package, only paying attention to the last line where the dollar sign is and makes his decision. Bob buys the cheapest equipment he can for the job. Does it work? Yes. Does it get the job done? Yes. Could he have given his customers a better presentation had he spent just a little more money upfront? Of course. But he didn't. Bob's theater will now forever live with this cheap business decision and in all probability within a few years will have spent MORE money paying techs to come service it with labor and part costs. This is the situation I have a problem with.
So let's take a closer look at Bob's third choice. What did he buy? Well, Bob is a supergenious and is super cheap. Without even batting an eye I can tell you that Bob now owns equipment made all at the same manufacturer. In this example, Bob's theater is now the proud owner of a complete Cinemaco booth. How do I know this? Had Bob purchased the Cinemaco projector, lamphouse and automation, but went elsewhere for the platter, Bob would have had to spend a LOT more of his precious money he likes to keep to himself. Buying all one brand of equipment is a decision made from cost alone, for most manufacturers would have damn near thrown that platter in for free after buying their projectors, lamphouses and automations. But enough about Bob. Bob has done his part and now no longer has to be bothered. This is now the tech's and the theater staff's problem.
Enter John the tech. John is now responsible for the upkeep of that booth's equipment, and is responsible any time something goes wrong and they lose a show. Yes that's right, John's job is relatively easy, but he has to deal with maintaining those damned Cinemaco platters!!! Needless to say, John is extremely frustrated. But what if it's worse? Let's say that Cinemaco has the worst customer service known to man and refuses to assist him? What is John to do? John is screwed because of a bad business decision and at this point only has 3 options.
#1 Beg and plead the corporate office to let him throw those Cinemaco platters in the dumpster and purchase good platters. (We can only hope John will videotape this event for download here.)
#2 Spend hour after hour and day after day making his own custom modifications and improvements to the horrible Cinemaco platter design. Lots of time and money is wasted here, but something has to be done because remember that Cinemaco has already got their money and has told John to stuff it that there is nothing wrong with their fabulous platters. John can not get support from the manufacturer and Bob will not support spending money on new platters. Eventually John will end up going with option #3.
#3 John throws his hands up in the air and says to the projectionist "if it throws a print, get a splicer and put it back together. If it scratches a print, just tell the customers that film gets that way." ...and he turns his back on the theater becoming that classic grumpy tech that everyone has had to work with at some time before. (Don't look surprised, everyone knows someone like this.)
Odds are John will start with #1 and after quickly being turned down proceed to #2. By the end of it all, he will find himself somewhere in between #2 and 3, or sitting firmly on #3.
Enter Frank the projectionist. Frank now has to deal with those damned contraptions and gets personally yelled at by the manager (who got yelled at by the angry customers) every time he loses a show or a print gets damaged. We don't even need to take this one further. Frank and the managers are definitely in hell!
So without wandering too far off topic, the problem I have with people saying to "work with what you have" and "buy the right tool for the job" is that the people who SHOULD be making these decisions DON'T. The people who SHOULD NOT be making the purchasing decisions DO...and they are usually based upon primarily or solely on cost. As such, and please pardon the expression, but those are bullshit sugar coated answers to a problem that lies elsewhere. In the end, more money is wasted because of a poor Cinemaco platter design and lack of support from the fine folks at Cinemaco.
So yes Bob is an idiot and made a bad purchasing decision. However in the end it all boils down to Cinemaco actually caring about their customers and assisting them any way they need AFTER the sale. This also includes making improvements to their product as issues turn up. Great manufacturers do this and I can name two specifically right off of the bat who I have seen first hand care to that extent: Christie and SPECO. (Check the re-review of Christie's projector and the review of SPECOs LP-280 for examples.) Both should be commended for their efforts and dedication to their products, and I recommend them highly. If you purchase equipment of theirs and a problem turns up, I can guarantee you that they will do whatever it takes and work through the problem with you until all is taken care of. That is professionalism at it's finest. 
Unfortunately, this industry has their share of Cinemacos. 
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By the way, I am finally starting to see a better performance out of my SCDCs after making some changes recommended by Rick at Strong and other field techs from this forum. There are still issues with them, but I will report more on this later.